Solving rising damp problem completely is always a 2-step process:
To solve rising damp there are several categories of solutions on the marketplace. Here is a quick overview of the most important ones.
In dealing with rising damp, the cheapest short-term solution (which can become very expensive in the long run) can be NOT dealing with the problem at all or doing short-term fixes.
Such solutions can include repainting, replastering, plasterboarding or the use of waterproof membranes with the intent to hide the visual manifestations of rising damp.
These solutions deal with the wall SURFACE only. They do not deal with the underlying dampness problem, they only mask it. The decay of the building fabric continues in the background, often at an accelerated pace, due to the use of modern, non-building-sympathetic building materials (e.g. cement), which can lead to expensive repairs later.
2. "Managing" It
Solutions in this category slow down rising damp or make it less intrusive. Because these solutions won’t stop the underlying capillary action, rising water and accompanying salts keep destroying the building fabric even if at a slower pace.
Chemical injections, electro-osmosis systems, various building- and wall ventilation systems, drainage and breathable lime plasters alone are some solutions in this category.
Chemical injections are the mainstream rising damp solution in the UK, but due to their invasive nature are less preferred and used in old heritage buildings. The success rate of chemical injections is limited by a number of technical factors due to the complex chemistry they depend on, as well as on the skill of the person administering it.
Electro-osmosis systems have been around since the 1970-80s, and as far as we know they have originated from Australia. In the UK they have been commercialized under the Lectros and Rentakill brands. The system applies a low voltage to the base of the walls via embedded titanium wires (electrodes). The electrical field in the walls creates an electro-osmotic flow which drags the water downwards.
Some of the factors responsible for the failure of these systems are the high salts content of the masonry. Salts can override the weak electrical field and stop the movement of water downwards. Certain types of building materials also natively limit the electro-osmotic flow, resulting in limited dehydration or dehydration failure.
Drainage, Heating, Ventilation & Lime Plasters
Drainage, heating, ventilation and lime plasters are the heritage- or conservation sector's default solution to rising damp. Although these factors are very important and necessary, in addressing rising damp they work with variable success. They give good results in certain buildings while they do very little in others against rising damp.
Based on a large number of observations and specialist measurements on a wide variety of old buildings we have identified a number of factors that are responsible for some of the failures of the drainage-ventilation-lime combination, as well as we quantified some of their limitations. We discuss some of these findings in the next section.
3. Permanent Solutions
There are a number of permanent solutions to rising damp, with both invasive and non-invasive options. Any permanent solution has to create a new damp proof course (DPC) or fix the existing one.
Wall cutting and non-invasive magnetic dehydration systems fall into this category.
This technology is mentioned for informative purposes only as it is practically not used in the UK. The wall is cut through horizontally with a rotating diamond chainsaw, then special steel plates are pushed into the brickwork to form a new solid damp proof course. This technology is obviously very invasive and we are not aware of any companies using it in the UK.
Magnetic Dehydration Systems
Magnetic dehydration systems have been around since the 1980s and they are the only non-invasive permanent solution to rising damp. These use clever electronics to reverse the water inside the wall fabric and send it back into the ground where it came from; also keeping it away permanently by creating a "wireless" damp proof course. These systems are detailed in one of the other chapters.
Which One Is Best For You?
Which solution you are going to choose will ultimately very much depends on the building and your personal preferences. There is no solution that fits all. You will have to decide what is most important to you:
- Budget (Option 1)
- Reassurance of widely adopted technologies (Option 2)
- Longevity, long-term peace of mind, while also adopting a modern but less known technology (Option 3)
Our 32-page PDF Dampness in Old Buildings publication below will help you with the decision. It is written in plain English and amongst others, covers the following topics:
- An overview of the main moisture sources in a building
- Does rising damp exists?
- How you can diagnose it, its visual signs with many pictures
- Damp proof course (DPC) solutions on the marketplace, their pros and cons
- Magnetic DPCs, the latest technical innovation
- The basics if renovating old buildings
- The top 5 renovation mistakes you must know about
- How to deal with condensation and mould... and more